The invention relates to a dispenser for media for securing to a support such as a reservoir or cylinder receptacle, a helve or the like with a mounting flange. The dispenser may comprise a volumetrically variable medium or pressure space such as a pump chamber from which the fluid medium such as a liquid, paste or cream, powder or gas can be conveyed under pressure to a medium outlet by moving a discharge and/or actuating head relative to the flange over a working stroke.
When securing the dispenser with the flange by a rotative, linear or axial movement, oriented jointing forces are necessary corresponding to a jointing resistance. The forces may increase sharply during fastening until the securing seat is attained. This seating may be a rigid or movable connection. For actuating the dispenser running forces are needed which are usually required to be introduced into the head and which likewise may increase commonly with the actuating path. The running forces correspond to a running resistance given by e.g. friction between piston and cylinder, by the resiliency of a return spring, or by the forces needed to actuate one or more valves etc.
The running resistance should be smaller than the jointing resistance. Therefore the head should not be loaded by the jointing force to avoid actuation of the head during jointing up to abutment on a stop or until the end position is attained. This stop can be encapsulated within the dispenser and may act on a counterstop of the piston unit, such as the end face of an elastic piston skirt which movably bounds, i.e. alters the volume of, the medium chamber. When this counter-stop is loaded with the jointing force it may be damaged or become leaky. Even in the absence of jointing forces it may be practical to prevent actuation up to the stop, despite the running force being fed into, e.g. as a tamperproof safeguard, childproof safeguard or the like.
An object of the invention is to overcome the disadvantages of known configurations or of the kind as described. Another object is to permit blocking of actuation against actuating forces substantially higher than any of the cited resistances. A further object is that the jointing force is not to be introduced partly or exclusively via the flange but via the head. Still another object is to permit the dispenser to be repeatedly translated into the blocked and unblocked states. A still further object is that the dispenser is straightforward in design and actuation.
The invention provides an apparatus which make it possible to join the head to the reservoir by a snap action joint without subjecting the dispenser to the snap action force. A blocking member and an actuating head, including a pump, are assemble to a medium reservoir while protecting the pump against actuation or excessive forces encountered during assembly. The blocking member can be disengaged to permit actuation.
A blocking member of the blocking means may be provided as a spacer between head and flange.(When the blocking means or its blocking member is reengaged after disegagement blocking of the actuation is repeatable.) In this arrangement the blocking member may be permanently mounted on the dispenser or totally separable from the dispenser.
The blocking member may prevent a dispenser body from being distended, for example by forming an outer shield or clamp which reinforces the dispenser body against being radially deformed.
The blocking member can be disengaged or engaged by spring forces so that it reliably holds on simple actuation. The associated actuating forces are oriented transverse to the operational and joining forces, and although the operation and joining forces may differ in direction, preferably they are parallel.
Preferably the blocking member covers a recess such as an annular gap between blocking faces to keep out dirt. The dispenser thus presents smoother outer surfaces in the blocked condition than in the unblocked condition.
The blocking member may be disengaged or engaged for securing the head to the actuating stem of the pump. The jointing forces needed to secure the head to the actuating stem are higher than the running force and may be higher or lower than the jointing forces of the flange.
The configuration according to the invention is particularly suitable for fasteners or closures including snap members, bayonet members or other rotary lock members as well as for fastening pumps having a body integral with or separate from the flange. Such pumps may be configured e.g. in accordance with the U.S. patent application Ser. No. 09/387124 to the features and effects of which reference is made for incorporating them in the invention.